diff --git a/doc/_templates/navbar.html b/doc/_templates/navbar.html
index d0979f4e10..883bedc56b 100644
--- a/doc/_templates/navbar.html
+++ b/doc/_templates/navbar.html
@@ -1,4 +1,4 @@
-<link rel="stylesheet" href="http://www.google.com/cse/style/look/default.css" type="text/css" />
+<link rel="stylesheet" href="https://www.google.com/cse/style/look/default.css" type="text/css" />
 <style type="text/css">
     a.navbar {
     color: {{ theme_linkcolor }};